According to an affidavit, authorities searched Martin's home, vehicle and two storage sheds Aug. 27, and found documents and digital information on devices and removable digital media.

Among the classified documents found, the government says, were six that contained sensitive intelligence, meaning they were produced through sensitive government sources or methods that are critical to national security issues. They were produced by a government agency in 2014.

"Martin at first denied, and later when confronted with specific documents, admitted he took documents and digital files from his work assignment to his residence and vehicle that he knew were classified," despite the fact that he didn't have the authorization to do so, according to the complaint.

Martin was arrested, and made an initial appearance in U.S. District Court in Baltimore on Aug. 29. He remains in custody.